METHYLATION OF SUGAR MERCAPTALS: II. L-ARABINOSE DIETHYL MERCAPTAL

1961 ◽  
Vol 39 (9) ◽  
pp. 1797-1800 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Silver Oxide

Methylation of L-arabinose diethyl mercaptal in tetrahydrofuran with methyl iodide and silver oxide yielded mainly 2-O-methyl-L-arabinose and a trace of 5-O-methyl-L-arabinose. The identity of the major component was inferred by its behavior on electrophoresis and confirmed by the preparation of the crystalline amide. The polymethylated components were not examined. 2-O-Methyl-L-arabono-γ-lactone, previously known as a sirup, has now been obtained crystalline.

STUDIES OF REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES.: XXVIII. THE STRUCTURE OF ISOPROPYLIDENE GLYCEROL

1930 ◽  
Vol 2 (3) ◽  
pp. 214-217 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain
Keyword(s):  
Methyl Iodide ◽  
Methyl Ether ◽  
Copper Sulphate ◽  
Silver Oxide ◽  
Condensation Product ◽  
Neutral Medium ◽  
Physico Chemical ◽  
Isopropylidene Glycerol

Isopropylidene glycerol, prepared in neutral medium by the action of anhydrous copper sulphate as condensing agent, was methylated with silver oxide and methyl iodide; the product yielded only glycerol α-methyl ether on hydrolysis, thus proving the absence of any six-membered ketal in the condensation product of glycerol and acetone.The properties of both glycerol α- and β-methyl ethers have been carefully redetermined.A table of the isomeric acetals and ketals summarising their physico-chemical constants is given, in view of their usefulness as "type compounds" in investigations relating to fats, carbohydrates and polysaccharides.

N-Methylamino acids in peptide synthesis. VII. Studies on the enantiomeric purity of N-methylamino acids prepared by various procedures

1977 ◽  
Vol 55 (5) ◽  
pp. 916-921 ◽  
Author(s):  
S. T. Cheung ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acid ◽  
Methyl Iodide ◽  
Peptide Synthesis ◽  
Liquid Ammonia ◽  
Silver Oxide ◽  
Sodium Hydride ◽  
Enantiomeric Purity ◽  
Amino Acid Analyzer ◽  
Pure Compounds ◽  
Optically Pure

The enantiomeric purity of N-methylamino acids and their derivatives obtained by various procedures has been examined by analysis with an amino-acid analyzer of the diastereomeric lysyl dipeptides formed by coupling them with a lysyl derivative. N-Benzyloxycarbonyl, and N-tert-butyloxycarbonyl,N-methylamino acids obtained by methylation of the parent derivative using sodium hydride and methyl iodide, and N-methylamino acids obtained by methylation of the p-toluenesulfonylamino acid followed by treatment with sodium in liquid ammonia, are optically pure. Compounds obtained by other procedures which include reductive alkylations or the use of silver oxide – methyl iodide are generally not optically pure.

METHYLATION OF SUGAR DITHIOACETALS: V. D-MANNOSE DIETHYL DITHIOACETAL

1963 ◽  
Vol 41 (10) ◽  
pp. 2500-2503 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Silver Oxide ◽  
The Other ◽  
Partial Methylation

Partial methylation of D-mannose diethyl dithioacetal in tetrahydrofuran with methyl iodide and silver oxide yielded 2-, 3-, and 6-O-methyl-D-mannose in the ratio of 12:1:1, respectively. The major component, 2-O-methyl-D-mannose, was characterized as the phenyl-hydrazone and the other isomers identified by electrophoresis. The Mg values of these mono-O-methyl ethers were recorded.

ipso Nitration. XXIII. Reactions of cyclohexadiene adducts from nitration of 4-ethyltoluene in acetic anhydride

1981 ◽  
Vol 59 (15) ◽  
pp. 2314-2327 ◽  
Author(s):  
Alfred Fischer ◽  
George N. Henderson
Keyword(s):  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Methyl Iodide ◽  
Methyl Ether ◽  
Potassium Hydroxide ◽  
Silver Oxide ◽  
Aluminum Hydride ◽  
Trifluoroacetic Anhydride ◽  
Aqueous Methanol

The diastereoisomers of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate (1) and 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate (2) are stereospecifically reduced to the corresponding nitrocyclohexadienols with aluminum hydride. Each dienol is stereospecifically methylated to the corresponding methyl ether with methyl iodide, silver oxide, and potassium hydroxide. Acid-catalysed solvolysis of the acetates 1 and 2 results in the substitution of the acetate moiety by other nucleophiles and these reactions are not stereospecific. The products of rearomatization of dienyl acetates, dienols, and dienyl methyl ethers depend on the acidity and ionizing power of the solvents and are readily explained in terms of reactions involving a nitrocyclohexadienyl cation or acetoxy- (hydroxy-, methoxy-)cyclohexadienyl cation as key intermediates. In the 4-acetoxy-4-alkylcyclohexadienyl cation 1,2-migration of the acetoxyl group is more rapid than alkyl migration, but 1,2-alkyl migration is faster than migration of the hydroxyl or methoxyl groups in the corresponding cations. 1-Ethyl-4-methoxy-4-methylcyclohexa-2,5-dien-1-ol and 4-ethyl-3-nitrotoluene are significant minor products in the solvolysis of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dien-1-ol in aqueous methanol. Nitration of p-ethyltoluene in the presence of sulfuric acid or in trifluoroacetic anhydride gives a mixture of 4-ethyl-2-nitro- and 4-ethyl-3-nitrotoluene in a 2:1 ratio.

Preparation of 5-Benzyluracil and 5-Benzylcytosine Nucleosides as Potential Inhibitors of Uridine Phosphorylase

1996 ◽  
Vol 61 (4) ◽  
pp. 627-644 ◽  
Author(s):  
Marcela Krečmerová ◽  
Hubert Hřebabecký ◽  
Antonín Holý
Keyword(s):  
Methyl Iodide ◽  
Thionyl Chloride ◽  
Alkaline Hydrolysis ◽  
Room Temperature ◽  
Silver Oxide ◽  
Uridine Phosphorylase ◽  
Cyclic Sulfite ◽  
Potential Inhibitors ◽  
Hydrolysis Of ◽  
Tin Tetrachloride

Reaction of 3,4,6-tri-O-acetyl-2-deoxyglucopyranosyl bromide (1) with silylated 5-benzyluracil and subsequent ammonolysis afforded α- and β-anomers of 5-benzyl-1-(2-deoxy-D-glucopyranosyl)uracil (2 and 3). Under catalysis with tin tetrachloride, silylated 5-benzyluracil reacted with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose to give 2',3',5'-tri-O-benzoyl-5-benzyluridine (10), which was converted into the 4-thio derivative 11 by reaction with Lawesson reagent. Debenzoylation of compound 11 afforded 5-benzyl-4-thiouridine (12), whereas its reaction with methyl iodide and deblocking gave 4-methylthiopyrimidine nucleoside 14. Amonolysis of derivative 12 at elevated temperature afforded 5-benzylcytidine (15). This reacted with thionyl chloride at room temperature to give cyclic sulfite 16 which on heating at 100 °C in dimethylformamide was converted into 5-benzyl-2,2'-cyclocytidine (17). Mild alkaline hydrolysis of compound 17 afforded 1-(β-D-arabinofuranosyl)-5-benzylcytosine (18). With boiling thionyl chloride, compound 15 formed 2',3'-cyclic sulfite 19 which on alkaline hydrolysis gave 5-benzyl-5'-chloro-5'-deoxycytidine (20). Compound 20 was reduced with tributylstannane to 5-benzyl-5'-deoxycytidine (21). Reaction of silylated 5-benzyluracil with 2-deoxy-3,5-bis(O-p-toluoyl)-D-ribofuranosyl chloride, catalyzed with mercury(II) bromide, afforded 5-benzyl-2'-deoxy-3',5'-bis(O-p-toluoyl)uridine (22) and its α-anomer 23. With Lawesson reagent, compound 22 gave 5-benzyl-4-thiouracil derivative 24 which was ammonolyzed to give 5-benzyl-2'-deoxycytidine (25). Analogously, compound 23 was converted into 5-benzyl-2-deoxy-α-cytidine (27). 5'-O-Benzoyl-5-benzyluridine (29) was converted into the 2,2'-anhydro derivative 30 which on reaction with hydrogen chloride afforded 3'-chloro-3'-deoxynucleoside 31. This compound was reduced with tributylstannane and the obtained 2'-deoxynucleoside 32 on treatment with thionyl chloride gave a mixture of erythro- and threo-3'-chloro-2',3'-dideoxynucleosides (33 and 34, respectively) which were reduced to 5'-O-benzoyl-5-benzyl-2',3'-dideoxyuridine (35). Compound 35 reacted with Lawesson reagent under formation of 4-thiouracil derivative 36 and this was deblocked to 5-benzyl-4-thio-2',3'-dideoxyuridine (37). On heating with ammonia, compound 37 was converted into 5-benzyl-2',3'-dideoxycytidine (38). Reaction of 4-thiouracil derivative with methyl iodide and subsequent hydrazinolysis afforded 4-hydrazino derivative 40 which was heated with silver oxide in ethanol to give a mixture of anomeric 5-benzyl-1-(2,3-dideoxyribofuranosyl)-2(1H)-pyrimidinones (42).

METHYLATION OF SUGAR DITHIOACETALS: IV. D-XYLOSE DIETHYL DITHIOACETAL

1962 ◽  
Vol 40 (10) ◽  
pp. 1899-1902 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Methyl Ether ◽  
Silver Oxide ◽  
Partial Methylation ◽  
Tetrahydrofuran Solution

Partial methylation of D-xylose diethyl dithioacetal in tetrahydrofuran with methyl iodide and silver oxide yielded 2-, 3-, and 5-O-methyl-D-xyloses in the ratio of 20:10:1. The poly-O-methylated components were not examined. The 2-O-methyl-D-xylose was identified as the crystalline sugar and the 3-O-methyl ether as the phenylosazone and p-bromophenylosazone. An alternative preparation of the dithioacetal in tetrahydrofuran solution is described.

Preparation of 6-amino-6-deoxy-2,3,4,5-tetra-O-methyl-D-gluconic acid and its derivatives

1984 ◽  
Vol 49 (11) ◽  
pp. 2665-2673 ◽  
Author(s):  
Karel Kefurt ◽  
Zdeňka Kefurtová ◽  
Jiří Jarý
Keyword(s):  
Methyl Iodide ◽  
Alkaline Hydrolysis ◽  
Gluconic Acid ◽  
Silver Oxide ◽  
Catalytic Reduction ◽  
Hydrolysis Of

6-Amino-6-deoxy-2,3,4,5-tetra-O-methyl-D-gluconic acid (I) was prepared by catalytic reduction of 6-azido-6-deoxy-2,3,4,5-tetra -O-methyl-D-gluconic acid (XVI) obtained by alkaline hydrolysis of the corresponding dimethylamine VIII or a mixture of dimethylamide VIII, amide XIV and methylamide XV. Amides VIII, XIV and XV are the products of alkylation of 6-azido-6-deoxy-D-gluconamide (VII) or 6-azido-6-deoxy-3,5-di-O-methyl-D-gluconamide (XIII), carried out with methyl iodide and silver oxide in N,N-dimethylformamide. Amides VII and XIII were prepared by amonolysis of 6-azido-6-deoxy-D-glucono-1,5-lactone (III) or 6-azido-6-deoxy-3,5-di-O-methyl-D-glucono-1,4-lactone (XII). Methylation of 6-amino-6-deoxy-D-gluconolactam (II) with methyl iodide and silver oxide in N,N-dimethylformamide afforded 6-deoxy-2,3,4,5-tetra-O-methyl-6-methylamino-D-gluconolactam (V) from which 6-deoxy-2,3,4,5-tetra-O-methyl-6-methylamino-D-gluconic acid (VI) was prepared.

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